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1.
Oper Dent ; 45(6): 664-676, 2020 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-32997740

RESUMEN

CLINICAL RELEVANCE: When a resin nanoceramic inlay is cemented using self-adhesive cement, a universal dentin adhesive can be applied to the prepared cavity. The application of the adhesive before self-adhesive cement placement provides similar or better interfacial adaptation than without the adhesive. SUMMARY: Purpose: The first objective of this study was to determine whether the luting material used for computer-aided design and computer-aided manufacture resin nanoceramic inlays affected interfacial adaptation. The second objective was to investigate whether application of a universal dentin adhesive before cementation affected interfacial adaptation. The final objective was to compare the inlay-side and dentin-side interfaces in the cement space.Methods and Materials: Seventy-four class I cavities were prepared on extracted human third molars. Cavities were optically scanned, and resin nanoceramic inlays were milled using Lava Ultimate blocks (3M ESPE). For the control groups, the fabricated inlays were cemented using Panavia V5 (Kuraray Noritake) or FujiCem 2 (GC). For the experimental groups, the teeth were randomly divided into groups I and II. Group I contained four subgroups using different luting materials; in all subgroups, the inlays were cemented and dual cured without pretreatment. Group II contained six subgroups in which inlays were cemented and dual cured after application of a universal dentin adhesive. After thermocycling, interfacial adaptation was measured using swept-source optical coherence tomography (SS-OCT) imaging and statistically compared among groups.Results: Interfacial adaptation was different depending on the luting material used (p<0.05). After application of a universal adhesive, some subgroups showed improved interfacial adaptation (p<0.05). In the comparison of inlay-side and dentin-side interfaces, no difference was found in interfacial adaptation (p>0.05).Conclusions: Interfacial adaptation for resin nanoceramic inlays differed with luting material. For some self-adhesive cements, application of a universal adhesive before cementation improved interfacial adaptation.


Asunto(s)
Incrustaciones , Tomografía de Coherencia Óptica , Resinas Compuestas , Diseño Asistido por Computadora , Preparación de la Cavidad Dental , Porcelana Dental , Humanos , Ensayo de Materiales , Cementos de Resina
2.
Rev Neurol (Paris) ; 175(9): 534-543, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31208813

RESUMEN

INTRODUCTION: Currently, no single diagnostic modality allows the distinction between early progression (EP) and pseudo-progression (Psp) in glioblastoma patients. Herein we aimed to identify the characteristics associated with EP and Psp, and to analyze their diagnostic value alone and in combination. MATERIAL AND METHODS: We reviewed the clinical, conventional magnetic resonance imaging (MRI), and molecular characteristics (MGMT promoter methylation, IDH mutation, and EGFR amplification) of glioblastoma patients who presented an EP (n=59) or a Psp (n=24) within six months after temozolomide radiochemotherapy. We analyzed relative cerebral blood volume (rCBV) and relative vessel permeability on K2 maps (rK2) in a subset of 33 patients using dynamic-susceptibility-contrast MRI. RESULTS: In univariate analysis, EP was associated with neurological deterioration, higher doses of dexamethasone, appearance of a new enhanced lesion, subependymal enhancement, higher rCBV and rK2 values. Psp occurred earlier after radiotherapy completion and was associated with IDH1 R132H mutation, and MGMT methylation. In multivariate analysis, rCBV, rK2, and MGMT methylation status were independently associated with EP and Psp. All patients with a methylated MGMT promoter and a low rCBV (<1.75) were classified as Psp while all patients with an unmethylated MGMT promoter and a high rCBV (≥1.75) were classified as EP. Among patients with discordant MGMT methylation and rCBV characteristics, higher rK2 values tended to be associated with EP. CONCLUSION: Combined analysis of MGMT methylation, rCBV and vessel permeability on K2 maps seems helpful to distinguish EP from Psp. A prospective study is warranted to confirm these results.


Asunto(s)
Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/terapia , Metilación de ADN , Metilasas de Modificación del ADN/genética , Enzimas Reparadoras del ADN/genética , Glioblastoma/diagnóstico , Glioblastoma/terapia , Imagen por Resonancia Magnética/métodos , Proteínas Supresoras de Tumor/genética , Adulto , Anciano , Biomarcadores de Tumor/análisis , Biomarcadores de Tumor/genética , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Quimioradioterapia/efectos adversos , Medios de Contraste , Metilasas de Modificación del ADN/análisis , Enzimas Reparadoras del ADN/análisis , Diagnóstico Diferencial , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Glioblastoma/genética , Glioblastoma/patología , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Pronóstico , Traumatismos por Radiación/diagnóstico , Traumatismos por Radiación/genética , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento , Proteínas Supresoras de Tumor/análisis
3.
Oper Dent ; 44(3): 221-226, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31046649

RESUMEN

This article describes the clinical protocol of using potassium iodide (KI) to reverse staining caused by silver diamine fluoride (SDF). SDF contains silver, fluoride, and ammonia. It has been used to arrest dental caries mainly in pediatric applications. The major drawback of SDF application is the dark staining of both teeth and restorative materials. Hence, its use on adult dentition is limited. Improving the esthetic outcome by stain reduction would greatly enhance the opportunity for SDF's universal use. This case demonstrates how KI can effectively reverse the staining.


Asunto(s)
Caries Dental , Yoduro de Potasio , Niño , Fluoruros Tópicos , Humanos , Compuestos de Amonio Cuaternario , Compuestos de Plata , Coloración y Etiquetado
5.
J Periodontal Res ; 53(2): 188-199, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29063599

RESUMEN

BACKGROUND AND OBJECTIVE: Diagnosis is a crucial step in periodontal treatment. The aim of this study was to evaluate the effectiveness of optical coherence tomography (OCT) for observation and determination of periodontal tissue profiles in vivo. MATERIAL AND METHODS: In experiment 1, refractive indices of purified water, porcine gingiva and human gingiva at 1330 nm were determined for the analysis of OCT images of periodontal tissues. In experiment 2, OCT examination was performed in the midlabial apico-coronal plane of mandibular anteriors in 30 Asian volunteers with healthy gingiva. Sulcus depth was measured on intra-oral photographs taken during probing. In the OCT images, the gingival, epithelial and connective tissue thickness, and the position of alveolar bone crest were determined and finally, the biologic width was measured. RESULTS: Refractive indices of purified water, porcine gingiva and human gingiva were 1.335, 1.393 and 1.397, respectively. Cross-sectional images of gingival epithelium, connective tissue and alveolar bone were depicted in real-time. The sulcular and junctional epithelium could be visualized occasionally. Laser penetration and reflection were limited to a certain depth with an approximate maximal imaging depth capability of 1.5 mm and OCT images of the periodontal structure were not clear in some cases. The average maximal thickness of gingiva and epithelium and biologic width at the mandibular anteriors were 1.06 ± 0.21, 0.49 ± 0.15 and 2.09 ± 0.60 mm, respectively. CONCLUSION: OCT has promise for non-invasive observation of the periodontal tissue profile in detail and measurement of internal periodontal structures including biologic width in the anterior region.


Asunto(s)
Diagnóstico por Imagen/métodos , Periodoncio/diagnóstico por imagen , Periodoncio/patología , Tomografía de Coherencia Óptica/métodos , Adulto , Proceso Alveolar/anatomía & histología , Proceso Alveolar/diagnóstico por imagen , Proceso Alveolar/patología , Animales , Tejido Conectivo/anatomía & histología , Tejido Conectivo/diagnóstico por imagen , Tejido Conectivo/patología , Diagnóstico por Imagen/instrumentación , Inserción Epitelial/anatomía & histología , Inserción Epitelial/diagnóstico por imagen , Inserción Epitelial/patología , Femenino , Encía/anatomía & histología , Encía/diagnóstico por imagen , Encía/patología , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Imagenología Tridimensional/métodos , Incisivo/anatomía & histología , Incisivo/diagnóstico por imagen , Incisivo/patología , Rayos Láser , Masculino , Mandíbula/anatomía & histología , Mandíbula/diagnóstico por imagen , Mandíbula/patología , Membrana Mucosa/diagnóstico por imagen , Membrana Mucosa/patología , Bolsa Periodontal/diagnóstico por imagen , Bolsa Periodontal/patología , Periodoncio/anatomía & histología , Fotografía Dental , Reproducibilidad de los Resultados , Porcinos , Tomografía de Coherencia Óptica/instrumentación , Adulto Joven
6.
J Dent Res ; 96(9): 992-998, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28521113

RESUMEN

The aims of this study were to observe the behavior of composite and formation of gaps during and immediately after light polymerization using swept source optical coherence tomography (OCT) and to compare the interfacial integrity of adhesives in cavities through 3-dimensional (3D) image analysis. Forty tapered cylindrical cavities (4-mm diameter, 2-mm depth) were prepared in bovine incisors and restored using Bond Force (BF), Scotchbond Universal Adhesive (SBU), OptiBond XTR (XTR), or Clearfil SE Bond 2 (SE2), followed by Estelite Flow Quick flowable composite. Real-time imaging was performed at the center of restoration by the OCT system (laser center wavelength: 1,330 nm; frequency: 30 KHz) during and up to 10 min after light curing. The 3D scanning was performed 0, 1, 3, 5, and 10 min after light curing. The percentages of sealed enamel and dentin interface area (E%, D%) were calculated using Amira software. In real-time videos, the initial gaps appeared as a bright scattered area mainly on dentin floor and rapidly progressed along the cavity floor. The timing, rate, and extent of gap formation were different among the specimens. From 3D visualization, gap progress could be seen on both enamel and dentin even after irradiation; furthermore, typical toroidal gap patterns appeared at the dentin floor of BF and SBU. XTR and SE2 showed nearly perfect sealing performance on the dentin floor up to the 10 min that images were recorded. From quantitative analysis, SE2 and XTR showed significantly higher E% and D% than other groups. SBU showed the smallest E% and BF showed a significantly smaller D% than other groups ( P < 0.05). In conclusion, real-time observation of composite placement and 3D quantification of interfacial gaps were implemented within the experimental limitations. Interfacial gap formation during polymerization of the composite depended on the adhesive system used. The formed gaps continued to propagate after composite light curing finished.


Asunto(s)
Resinas Compuestas/química , Curación por Luz de Adhesivos Dentales , Tomografía de Coherencia Óptica , Animales , Bovinos , Luces de Curación Dental , Esmalte Dental , Dentina , Imagenología Tridimensional , Incisivo , Ensayo de Materiales , Polimerizacion , Cementos de Resina , Programas Informáticos , Propiedades de Superficie , Grabación en Video
7.
Clin Oral Investig ; 21(8): 2637-2644, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28176000

RESUMEN

OBJECTIVES: The aim of this study was to evaluate factors associated with the incidence of erosive tooth wear (ETW) among adults at different ages in Tokyo using multifactorial logistic regression analysis. MATERIALS AND METHODS: The study sample consisted of a total of 1108 subjects aged 15 to 89 years in Tokyo, Japan. Two examiners evaluated ETW in a full-mouth recording. The subjects were asked to complete a self-administered daily diet, habit, and health condition questionnaire. Subjects who had frequent acid consumption or gastric reflux and at least one tooth with initial enamel wear were placed in the ETW-positive group, and the remainder of the subjects was placed in the ETW-negative group. Logistic regression analyses were carried out to identify factors collectively associated with ETW. RESULTS: Logistic regression analysis showed that greater frequencies of carbonated or sports drink consumption were associated with higher incidence of ETW for all age groups except for 70-89 years. Adults in the 30-39-year group who reported suffering from heartburn were about 22.3 times more likely to develop ETW, while 40-49-year adults who had repeated vomiting were about 33.5 times more likely to exhibit ETW compared with those who did not experience vomiting. CONCLUSION: Age-specific dietary habits were clearly observed among adults at different ages in Tokyo, and there were significant differences in intrinsic and extrinsic factors between ETW-positive and ETW-negative groups for each age group. CLINICAL RELEVANCE: Both greater frequency of carbonated and sports drink consumption were associated with higher incidence of ETW among adults at different ages in Tokyo.


Asunto(s)
Erosión de los Dientes/epidemiología , Erosión de los Dientes/etiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Bebidas , Dieta , Femenino , Humanos , Incidencia , Modelos Logísticos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Encuestas y Cuestionarios , Tokio/epidemiología
8.
J Dent Res ; 96(3): 308-314, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-27872333

RESUMEN

The aim of this study was to nondestructively analyze enamel crack behavior on different areas of teeth using 3D swept source-optical coherence tomography (SS-OCT). Ten freshly extracted human teeth of each type on each arch ( n = 80 teeth) were inspected for enamel crack patterns on functional, contact and nonfunctional, or noncontact areas using 3D SS-OCT. The predominant crack pattern for each location on each specimen was noted and analyzed. The OCT observations were validated by direct observations of sectioned specimens under confocal laser scanning microscopy (CLSM). Cracks appeared as bright lines with SS-OCT, with 3 crack patterns identified: Type I - superficial horizontal cracks; Type II - vertically (occluso-gingival) oriented cracks; and Type III - hybrid or complicated cracks, a combination of a Type I and Type III cracks, which may or may not be confluent with each other. Type II cracks were predominant on noncontacting surfaces of incisors and canines and nonfunctional cusps of posterior teeth. Type I and III cracks were predominant on the contacting surfaces of incisors, cusps of canines, and functional cusps of posterior teeth. Cracks originating from the dental-enamel junction and enamel tufts, crack deflections, and the initiation of new cracks within the enamel (internal cracks) were observed as bright areas. CLSM observations corroborated the SS-OCT findings. We found that crack pattern, tooth type, and the location of the crack on the tooth exhibited a strong correlation. We show that the use of 3D SS-OCT permits for the nondestructive 3D imaging and analysis of enamel crack behavior in whole human teeth in vitro. 3D SS-OCT possesses potential for use in clinical studies for the analysis of enamel crack behavior.


Asunto(s)
Esmalte Dental/lesiones , Imagenología Tridimensional , Tomografía de Coherencia Óptica/métodos , Fracturas de los Dientes/diagnóstico , Síndrome de Diente Fisurado/diagnóstico , Esmalte Dental/patología , Humanos , Técnicas In Vitro , Microscopía Confocal/métodos
9.
Drug Res (Stuttg) ; 66(10): 532-538, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27463028

RESUMEN

Background: Cancer is one of the leading causes of death worldwide. Despite certain advances in cancer therapy, still there is considerable demand for developing efficient therapeutic agents. Nowadays, there is a rising interest in the use of natural-based anti-cancer drugs. In this study, the cytotoxicity of farnesiferol C and microlobin isolated from Ferula szowitsiana was investigated against MCF-7, HeLa and KYSE cancer cell lines. In addition, the mechanism of binding of these compounds to apoptotic proteins (Bax, Bak and Bcl-2) was analyzed by an in silico method. Materials and methods: We used MTT assay in order to assess the cytotoxicity of compounds against cancer cell lines. For in silico study, the AutoDock 4 was adopted. Results and discussion: According to the in vitro findings, in general, farnesiferol C showed significant cytotoxicity at higher concentrations (>50 µM) following 48 and 72 h incubation with the selected cancer cells; however, microlobin exhibited almost no activity at concentrations up to 100 µM. The in silico results revealed that both compounds could bind to Bax more efficiently rather than to Bcl-2 or Bak proteins. Conclusion: The results obtained by our preliminary in vitro and in silico studies suggest that these compounds might induce apoptosis through Bax activation; however further studies, either in vitro or in vivo are needed to clarify these activities.


Asunto(s)
Cumarinas/farmacología , Simulación del Acoplamiento Molecular , Sesquiterpenos/farmacología , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Cumarinas/aislamiento & purificación , Relación Dosis-Respuesta a Droga , Ferula/química , Humanos , Unión Proteica , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Sesquiterpenos/aislamiento & purificación , Proteína Destructora del Antagonista Homólogo bcl-2/metabolismo , Proteína X Asociada a bcl-2/metabolismo
10.
Aust Dent J ; 61(3): 366-73, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-26573239

RESUMEN

BACKGROUND: The aim of this randomized controlled study was to evaluate the clinical performance of a highly filled flowable composite compared to a conventional paste-type composite in direct posterior restorations after 36 months. METHODS: A total of 58 mid-size to extensive posterior composite restorations were randomly placed in 32 patients, mean age of 43.9 years (range 25-76), using either a conventional composite Estelite Sigma Quick (Conventional) or a highly filled flowable composite G-aenial Universal Flo with a two-step self-etch adhesive. The restorations were evaluated after placement (baseline) and at 6, 12, 24 and 36 months according to the FDI criteria. RESULTS: At the 36-month follow-up, 42 restorations were evaluated in 21 patients. After 36 months, the difference between highly filled flowable and conventional restorations was not statistically significant with respect to all evaluation parameters (p < 0.05). No secondary caries was observed. CONCLUSIONS: The highly filled flowable composite showed a comparable clinical effectiveness as the conventional paste composite in posterior restorations over 36 months.


Asunto(s)
Resinas Compuestas/uso terapéutico , Caries Dental/terapia , Diente Molar , Adulto , Anciano , Caries Dental/patología , Restauración Dental Permanente/métodos , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Resultado del Tratamiento
11.
J Dent Res ; 94(8): 1070-7, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26082389

RESUMEN

This study investigated the influence of adhesives and marginal sealing on demineralization progress using optical coherence tomography (OCT). Cavities (4 × 2 mm) were prepared in bovine incisors and restored using Clearfil SE Protect (SP), Bond Force (BF), Scotchbond Universal (SB), or G-Bond Plus (GB), followed by Estelite Flow Quick flowable composite. The control group received no adhesive (n = 10). After 3-d incubation in artificial saliva and 10,000 thermal cycles, gaps at enamel and dentin margins were measured at 8 locations on cross-sectional images obtained from each restoration using swept-source OCT at 1310-nm wavelength. Specimens were demineralized using acidified gel (pH = 4.5) for 5 wk and scanned every week to monitor the lesion progress at the same marginal locations. Repeated-measures analysis of variance showed that demineralization period and adhesive type and their interaction had a significant effect on the lesion size in both substrates (P < 0.001). SP, BF, and SB had significantly lower enamel and dentin initial gaps than the control and GB (P < 0.05). Enamel lesion progress was slower in the fluoride-releasing adhesives SP and BF and significantly different from SB, GB, and the control (P < 0.001). SP and BF dentin lesions were significantly different from GB and the control (P < 0.001), but not from SB (P > 0.05). A significant positive correlation (P < 0.05) was found between initial gap length and formed lesion size in both substrates, which was stronger in enamel (r = 0.63) than dentin (r = 0.35). Microgaps forming at the margins of restorations depend on adhesives and significantly contribute to the progress of demineralization around the margins, while fluoride release may decrease the rate of progression.


Asunto(s)
Resinas Compuestas/química , Recubrimiento Dental Adhesivo/métodos , Filtración Dental/diagnóstico , Cementos de Resina/química , Desmineralización Dental/inducido químicamente , Desmineralización Dental/diagnóstico , Animales , Bovinos , Adaptación Marginal Dental , Técnicas In Vitro , Metacrilatos , Microscopía Confocal , Tomografía de Coherencia Óptica
12.
Oper Dent ; 40(1): E28-39, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25299704

RESUMEN

This study assessed dentin-resin interface integration in Class I cavities restored with simplified adhesives by using a focused ion-beam milling (FIB) and transmission electron microscope (TEM). Class I cavities (1.5-mm depth with dentin thickness of ∼0.5 mm, 4-mm length, and 2-mm width) were prepared on freshly extracted, sound human molars. Two all-in-one adhesive systems (Scotchbond/Single Bond Universal [SUD] and Xeno-V(+) [X5D]) were used and compared with a two-step etch-and-rinse system (Prime&Bond NT [NTD]). The adhesives were applied according to the manufacturers' guidelines. A universal resin composite (Filtek Z350 XT Universal) was used to restore the cavities in one bulk filling and was irradiated at 550 mW/cm(2) for 40 seconds by a quartz-tungsten-halogen light (Optilux 501). After exposure to liquid nitrogen coolant, the specimens were milled to nanoscale thickness by FIB to view and then assess the area of dentin-resin interface by TEM. Unlike the unfilled X5D, a noticeably smooth transition zone at the dentin-resin interface was shown for the SUD and NTD adhesives. The SUD demonstrated an uneven hybrid layer with clearly demineralized collagen bundles. Ultramorphologically, dispersed needlelike apatite crystals were detected within the partially demineralized dentin or the hybrid layer of both compositionally different all-in-one simplified adhesives. Conversely, these crystals were entirely absent from the hybrid layer of the etch-and-rinse NTD adhesive. In the X5D group, a bright band was noted beneath the hybrid layer. The methacryloxydecyl dihydrogen phosphate monomer containing ultramild self-etch adhesive (SUD) was still validated in terms of its capability in dentin adhesion.


Asunto(s)
Cementos Dentales/uso terapéutico , Dentina/ultraestructura , Resinas Sintéticas/uso terapéutico , Grabado Dental/métodos , Restauración Dental Permanente/métodos , Recubrimientos Dentinarios/uso terapéutico , Humanos , Microscopía Electrónica de Transmisión , Cementos de Resina/uso terapéutico
13.
Ann R Coll Surg Engl ; 96(7): e20-1, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25245718

RESUMEN

Although basal cell carcinoma is a very common malignancy, metastasis from this tumour is extremely rare. For this reason, many plastic surgeons, dermatologists and physicians dealing with skin malignancies consider this as a locally invasive malignancy. We present a rare case of metastatic basal cell carcinoma manifested as a bronchial tumour. This case highlights the fact that despite basal cell carcinoma's local invasive potential, the possibility of distant metastasis still exists and clinicians should therefore be cautious about interpreting extracutaneous symptoms. Chest physicians should always consider the possibility of this rare tumour in the lungs in patients with a history of large basal cell carcinomas in the head and neck region.


Asunto(s)
Neoplasias de los Bronquios/secundario , Carcinoma Basocelular/secundario , Cuero Cabelludo/patología , Neoplasias Cutáneas/patología , Anciano , Neoplasias de los Bronquios/patología , Neoplasias de los Bronquios/terapia , Carcinoma Basocelular/patología , Carcinoma Basocelular/terapia , Terapia Combinada , Procedimientos Quirúrgicos Dermatologicos/métodos , Estudios de Seguimiento , Humanos , Masculino , Invasividad Neoplásica/patología , Estadificación de Neoplasias , Radioterapia Ayuvante , Neoplasias Cutáneas/terapia , Resultado del Tratamiento
14.
Eur J Prosthodont Restor Dent ; 22(1): 43-7, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24922999

RESUMEN

This study evaluated the microleakage of resin cements in the pulp chamber dentin. Fifty specimens of sound human molars were divided into five groups. Composite cores cemented using Clearfil SA Luting in the first group to a dried dentin and in the second group to a moistened dentin and then light-cured. In third and fourth groups, cement was placed on dried and moistened dentin and self-cured respectively. In fifth group, composite cores were cemented by Panavia F2.0. After thermocycling, microleakage was evaluated using fluid filtration technique. The highest microleakage mean value was observed in the group with light-cured to a dry dentin. The mode of curing in contrast to moisture value had significant effect on microleakage. The microleakage of self- adhesive resin cement used in this study was lower in case of self cured than in case of light-cured and was not related to the dentin surface moisture.


Asunto(s)
Filtración Dental/clasificación , Cavidad Pulpar/ultraestructura , Dentina/ultraestructura , Curación por Luz de Adhesivos Dentales/métodos , Cementos de Resina/química , Auto-Curación de Resinas Dentales/métodos , Agua/química , Resinas Compuestas/química , Materiales Dentales/química , Desecación , Filtración/instrumentación , Humanos , Ensayo de Materiales , Metacrilatos/química , Técnica de Perno Muñón/instrumentación , Temperatura , Factores de Tiempo
15.
Caries Res ; 47(1): 18-26, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23051596

RESUMEN

Recent advances in the field of optics have enabled accurate and localized measurement of optical properties of biological substrates. This work aimed to elucidate the relationship between the local refractive index (n) and mineral content (MC) of enamel and dentin. De- and remineralized lesions in bovine enamel and dentin blocks were sectioned into 300- to 400-µm-thick slices, and placed on a metal plate to capture images of sound, de- and remineralized regions transversely by optical coherence tomography. Mean n at each depth level of the lesion (20- or 40-µm steps for enamel or dentin) was measured by the optical path length-matching method and used to plot n through lesion depth. The specimens were further polished and processed for transverse microradiography for analysis of MC. The n and MC ranged from 1.52 to 1.63 and 50 to 87 (vol.%) in enamel, and from 1.43 to 1.57 and 11 to 48 (vol.%) in dentin, respectively. Strong, positive linear correlations were found between n and MC (Pearson's r = 0.95 and 0.91 for de- and remineralized enamel, and r = 0.94 and 0.91 for dentin, respectively, p < 0.001). Experimental data were validated with a theoretical calculation of n from MC. De- and remineralization of enamel and dentin resulted in measurable changes of n, and, in turn, MC changes of the tissue could be estimated with good accuracy from this long-known optical property by the new analytical approach. Compositional changes of enamel crystallites after remineralization affect n.


Asunto(s)
Esmalte Dental/química , Dentina/química , Minerales/análisis , Ácido Acético/análisis , Algoritmos , Animales , Apatitas/análisis , Cloruro de Calcio/análisis , Bovinos , Cristalografía , Durapatita/análisis , Procesamiento de Imagen Asistido por Computador/métodos , Microrradiografía , Fosfatos/análisis , Compuestos de Potasio/análisis , Refractometría , Azida Sódica/análisis , Fluoruro de Sodio/análisis , Tomografía de Coherencia Óptica/métodos , Desmineralización Dental/metabolismo , Remineralización Dental
16.
J Dent Res ; 91(6): 586-91, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22476867

RESUMEN

Transverse microradiography (TMR) is considered as the gold standard technique for the evaluation of enamel lesions. Micro-computed tomography (µCT) has the advantage of non-destructive measurements, but the beam-hardening effect with polychromatic x-rays is a major drawback. To date, no study has validated µCT against TMR. The objective of this study was to validate µCT measurements of enamel lesions under various x-ray conditions and software beam-hardening correction (BHC) against TMR. Human molars with natural white-spot lesions were scanned for 5 min by µCT at 100 kV in different conditions: 50 µA (0.5-mm Al filter), 165 µA (0.5-mm Al/0.3-mm Cu), and 200 µA (0.5-mm Al/0.4-mm Cu), with or without BHC. Grayscale values were converted into mineral density values using phantoms. Thin sections at the same positions were then prepared for TMR. Lesion depth (LD; µm) and mineral loss (ΔZ; vol%µm) were compared between µCT and TMR by Pearson's correlations. µCT measurements correlated well with TMR under all conditions (p < 0.001, r > 0.86 for LD and ΔZ), except for 0.5-mm Al without BHC (p > 0.05). Even without BHC, combined Al/Cu filters successfully reduced the beam-hardening effect. µCT can be used as a non-destructive alternative to TMR with comparable parameters for the study of enamel lesions.


Asunto(s)
Caries Dental/diagnóstico por imagen , Esmalte Dental/diagnóstico por imagen , Microrradiografía , Intensificación de Imagen Radiográfica/métodos , Microtomografía por Rayos X , Adulto , Aluminio , Artefactos , Cobre , Filtración/métodos , Humanos , Tercer Molar/patología , Fantasmas de Imagen , Reproducibilidad de los Resultados , Adulto Joven
17.
J Dent Res ; 91(4): 370-5, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22337700

RESUMEN

The aim of this study was to assess the effect of chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and a low concentration of fluoride (F) on the hardness of enamel subsurface lesions, utilizing a double-blind, randomized, and controlled in situ model. Fifteen individuals wore removable lingual appliances with 3 bovine-enamel insets containing subsurface demineralized lesions. Three times a day for 14 days, they chewed one of the 3 chewing gums (placebo, POs-Ca, POs-Ca+F). After the treatment period, cross-sectional mineral content, nanoindentation hardness, and fluoride ion mapping by time-of-flight secondary ion mass spectrometry (TOF-SIMS) were evaluated. Although there were no statistical differences in overall mineral content and hardness recovery rates between POs-Ca and POs-Ca+F subsurface lesions (p > 0.05), nanoindentation at 1-µm distance increments from the surface showed statistical differences in hardness recovery rate between POs-Ca and POs-Ca+F in the superficial 20-µm region (p < 0.05). Fluoride mapping revealed distribution of the ion up to 20 µm from the surface in the POs-Ca+F group. Nanoindentation and TOF-SIMS results highlighted the benefits of bioavailability of fluoride ion on reinforcement of the superficial zone of subsurface lesions in situ (NCT01377493).


Asunto(s)
Fluoruro de Calcio/administración & dosificación , Cariostáticos/administración & dosificación , Goma de Mascar , Esmalte Dental/efectos de los fármacos , Desmineralización Dental/tratamiento farmacológico , Animales , Disponibilidad Biológica , Fluoruro de Calcio/farmacocinética , Cariostáticos/farmacocinética , Bovinos , Esmalte Dental/patología , Método Doble Ciego , Fluoruros/análisis , Dureza , Humanos , Microrradiografía , Minerales/análisis , Placebos , Espectrometría de Masa de Ion Secundario , Desmineralización Dental/patología , Remineralización Dental
18.
Int Endod J ; 45(5): 462-8, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22211861

RESUMEN

AIM: To investigate the effect of cyclic fatigue on nickel-titanium (NiTi) endodontic instruments using a nano-indentation test. METHODOLOGY: Eight ProFile NiTi rotary instruments (size 30, taper 0.06; Dentsply Maillefer, Ballaigues, Switzerland) were tested using a cyclic fatigue set-up until fracture. The fractured instruments and eight new NiTi instruments of the same size and taper were used for a nano-indentation test on the internal surfaces of a NiTi instruments in the region just adjacent to their fractured edge (group I) and in the same region of the new group (group II), and the cutting part beside the shaft for both instruments [group III (fractured) and group IV (new)]. Data were statistically analyzed using one-way analysis of variance and Games-Howell post hoc test. The alpha-type error was set at 0.05. RESULTS: Significant differences in terms of hardness and elastic modulus for each group (P < 0.05) were found, with group I having the lowest mean values followed by group III. Additionally, standard deviations increased remarkably after failure, as represented by groups I and III. CONCLUSION: The nano-indentation technique can be applied to determine the performance and the failure mechanism of NiTi instruments. The fatigue process revealed a significant decrease in the hardness and elastic modulus of the NiTi instrument. As indicated by the low hardness, the fatigue process did not result in work hardening but rather work softening.


Asunto(s)
Aleaciones Dentales/química , Níquel/química , Preparación del Conducto Radicular/instrumentación , Titanio/química , Análisis del Estrés Dental/instrumentación , Módulo de Elasticidad , Diseño de Equipo , Falla de Equipo , Dureza , Humanos , Ensayo de Materiales , Nanotecnología , Rotación , Estrés Mecánico , Propiedades de Superficie , Factores de Tiempo
19.
J Dent ; 39(6): 405-13, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21453746

RESUMEN

OBJECTIVES: The present study evaluated the effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and CPP-ACP with 900 ppm fluoride (CPP-ACPF) pastes on inhibition of enamel demineralization over time, using polychromatic micro-computed tomography (micro-CT). METHODS: Enamel blocks were prepared from bovine teeth. The specimens were each treated by one of the following agents, 30 min daily for 7 days: deionized water (negative control); CPP-ACP paste; CPP-ACPF paste; and NaF solutions (positive controls) (90, 900, and 9000 ppm F). After treatment, the specimens were immersed in a demineralizing solution (pH 4.5) for 24, 72, and 120 h. Mean mineral loss (ML) and lesion depth (LD) after each period were determined from mineral density profiles obtained using micro-CT. RESULTS: ML values in all the treatment groups were significantly smaller than those in the control group after 72 and 120 h of demineralization (p < 0.05, two-way ANOVA and t-test with Bonferroni correction). ML values in CPP-ACPF and NaF solution groups were significantly smaller compared to CPP-ACP group after 72 h (p < 0.05). LD values in the CPP-ACPF and all the NaF solutions groups were significantly smaller compared to the control group after 120 h (p < 0.05). The 9000 ppm F group showed the lowest nominal ML and LD values. CONCLUSIONS: The application of CPP-ACP or CPP-ACPF pastes to sound enamel surfaces resulted in inhibition of enamel demineralization, and a better effect was noted for the latter paste. Quantitative assessment using polychromatic micro-CT demonstrated to be useful for detecting mineral density changes.


Asunto(s)
Cariostáticos/farmacología , Caseínas/farmacología , Esmalte Dental/efectos de los fármacos , Fluoruro de Sodio/farmacología , Desmineralización Dental/patología , Microtomografía por Rayos X/métodos , Animales , Cariostáticos/administración & dosificación , Caseínas/administración & dosificación , Bovinos , Concentración de Iones de Hidrógeno , Imagenología Tridimensional/métodos , Ensayo de Materiales , Minerales/análisis , Fluoruro de Sodio/administración & dosificación , Soluciones , Suspensiones , Temperatura , Factores de Tiempo , Desmineralización Dental/prevención & control
20.
J Dent Res ; 90(2): 246-50, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21084716

RESUMEN

Bioglass 45S5 is a bioactive glass that can create a layer of calcium-phosphate crystals on mineralized hard tissues. In this study, 45S5 bioglass was mixed with phosphoric acid and irradiated with CO(2) laser and examined as a possible aid in the treatment of dentin hypersensitivity. The dentinal surface modified by the aforementioned technique was chemically and micro-morphologically examined with a field emission scanning electron microscope (FE-SEM) equipped with an energy-dispersive x-ray spectroscope (EDS), and the crystalline structures of the examined dentinal surfaces were examined by x-ray diffraction (XRD). Moreover, the mechanical properties of the newly formed layer were examined by nanoindentation. The results showed that 45S5 bioglass could occlude the dentinal tubule orifices with calcium-phosphate crystals. The application of CO(2) laser potentially improved the mechanical organization of these crystals.


Asunto(s)
Cerámica/uso terapéutico , Desensibilizantes Dentinarios/uso terapéutico , Sensibilidad de la Dentina/tratamiento farmacológico , Dentina , Láseres de Gas/uso terapéutico , Fosfatos de Calcio , Cristalografía por Rayos X , Dentina/química , Dentina/ultraestructura , Módulo de Elasticidad , Vidrio , Dureza , Humanos , Microscopía Electrónica de Rastreo/instrumentación , Espectrometría por Rayos X , Agua
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